INFECTIOUS MASTITIS IN GENERAL 15 



infected. In old wounds this is prevented by the inflam- 

 matory connective-tissue formation. 



Protection of Wounds Against Infection. — The 

 leucocytic wall forms the most important protection against 

 infection of the wound. But since the wall of leucocytes 

 is only an evidence of inflammation, that process plays 

 a very important part against infection. 



Finally the inflammatory connective-tissue wall forms 

 a very good obstacle to the progress of infection, as it 

 circumscribes it. 



Predisposing Factors to the Infection. — The nutrient 

 fluids, blood, lymph, and milk which infiltrate the udder 

 wound, predispose it to infection more than any other 

 wound because of the favorable nutrient conditions for the 

 infectious organisms and because the wound itself is a 

 good thermostat. 



The greater the blood infiltration, the more widespread 

 the death of cells, and the more saturated with fluids the 

 wound is, just so much better it is for infection. It is 

 broken down by the bacteria which as a rule live more 

 easily on dead than on hving media. In the latter case 

 they are more directly exposed to healthy phagocytes. 



THE BLOOD AS A PORT OF INFECTION 



In order that the blood coming into the udder may be a 

 port of infection, it is necessary that we have a blood-infec- 

 tion, that is, that the infectious organisms be in the blood 

 stream. 



Blood-infection. — The blood can become entirely or 

 partially infected, that is, general blood-infection (bac- 

 teremia), or partial blood-infection. 



A partial blood-infection is possible in this way, that 

 the infectious organism be deposited in the organs or be 

 transported to the organs from the blood by leucocytes. 



